View of the archaeological site of Herculaneum. Herculaneum was originally a port city. Today the sea, visible in the distance, is several hundred meters away. Photo: Francesca Piqué

View of Herculaneum with Mount Vesuvius in the distance. When Vesuvius erupted in AD 79, Herculaneum was submerged under pyroclastic surges and flows. The ancient city now lies under a layer of tuff more than 15 meters (50 feet) thick. Two- and three-story buildings have been excavated over the years. Photo: Francesca Piqué

The original shoreline of Herculaneum, where work is currently taking place as part of the Herculaneum Conservation Project. Under the arches, several hundred bodies were discovered of those presumably trying to escape the eruption by fleeing to the sea. Photo: Giacomo Chiari

Wall paintings at the Casa del Gran Portale, with Giacomo Chiari (GCI) and Francesca Piqué (GCI consultant) collecting samples using a special aspirator. The powder removed by scalpel from the painting is then deposited on a porous filter inside a vial. The sealed vial is then opened in the lab and the powder tested with X-ray diffraction. This technique is very useful when sampling in windy conditions and is an excellent alternative to collecting small powdered samples on pieces of paper. Photo: Giorgio Torraca.

Remains of Herculaneum. The site was first discovered in 1709, and exploration was carried out by tunnel in the 18th and 19th centuries. Modern archeological excavations have yielded richly decorated houses and a theater with fine marble and bronze sculptures, mosaics, and paintings. It is estimated that roughly one-third of the ancient town has been excavated, with the remainder lying under the modern town of Ercolano. Photo: Francesca Piqué

A perfectly preserved mosaic floor from the famous Villa of the Papyri. The villa inspired the design of the Getty Villa in Malibu, California. Photo: Francesca Piqué

Giacomo Chiari (GCI) using Polynomial Texture Mapping (PTM) on the mosaic of Neptune and Amphitrite. PTM documents the texture of an object by taking several pictures under different angles of incident light. The camera remains stationary while the light source rotates around the object. The black ball captures the reflection and a computer calculates the light direction. The angles of illumination on the PC screen are controlled by the mouse. Photo: Giorgio Torraca

A March 2008 meeting of the multidisciplinary Herculaneum Conservation Project team. Team members meet regularly to discuss issues related to the project. Photo: Francesca Piqué

Detail of a deteriorated wall painting representing a satyr and a bacchant from the tablinum of the House of the Bicentenary. Historical images of these paintings after excavation in the 1930s illustrate an alarming rate of deterioration and loss in recent times. Historical and archival research are part of the Herculaneum Conservation Project. Photo: Francesca Piqué

Detail of the aforementioned wall painting recorded in raking light and illustrating the severe deterioration of the paint layer. The GCI will apply scientific investigations to identify and address specific deterioration problems in order to facilitate the conservation of excavated items in situ. Photo: Francesca Piqué

Plaster and wall painting deterioration at Herculaneum. Such deterioration is severe at the site and is often associated with the presence of soluble salts. Photo: Francesca Piqué

A detail of deterioration of a wall painting at Herculaneum. Photo: Francesca Piqué

Project team members preparing injection grouts to reattach plasters and wall paintings at Herculaneum. Detachment of plaster and wall paintings is a widespread problem at the site. The knowledge gained through the GCI's Injection Grouts project is being applied to help improve grouting methods used at Herculaneum. Photo: Leslie Rainer

Conservator injecting grout into wall to reattach delaminated plaster to the support. Grouting—the injection of a liquid mortar with adhesive and bulking properties—addresses the lack of adhesion between plasters and primary supports. The invasive, non-reversible nature of grouts and the difficulty of assessing their efficacy makes this one of the most difficult conservation interventions. Photo: Leslie Rainer

Laser Speckle Interferometry being used on wall paintings at the site. This technique is used before and after grouting interventions to assess in their efficacy. Further assessment is again carried out about six months after the initial intervention. Laser Speckle Interferometry is potentially very useful in determining areas of plaster detachment and in monitoring stability over time. Photo: Francesca Piqué

David Carson (GCI) and Beril Bicer-Simsir (GCI) using Laser Speckle Interferometry on a mosaic at the House of Neptune and Amphitrite to record areas of detachment. The green light seen at the lower right corner of the mosaic is from the laser. Photo: Francesca Piqué

Alessandra De Vita (HCP) and Beril Bicer-Simsir (GCI) examining areas of plaster detachment by tapping the surface and recording the results graphically on images of the paintings. Photo: Giacomo Chiari

David Carson (GCI) tapping a wall surface to activate movement while using Laser Speckle Interferometry. The movement can be activated both by light touch—which requires access to the surface (as in this image)—or remotely by sound activation using a speaker. Photo: Giacomo Chiari